There are two main techniques to solve the HFB equation (REF ). As
well known from basic quantum mechanics, if two operators commute, it is
possible to find a common eigenbasis. One popular approach to solving the HFB
equation thus involves recasting (REF ) into a non-linear eigenvalue
problem which is solved iteratively. Alternatively, one may view the HFB
equation as a minimization problem. By suitably parameterizing the HFB wave
function thanks to the Thouless theorem, one can adapt gradient techniques to
minimize the energy. These two techniques are discussed in details in
[1]}.
